OFFSET
1,2
LINKS
Eric Weisstein's World of Mathematics, Totient Function.
MATHEMATICA
Table[Sum[EulerPhi[i*j*k]/EulerPhi[j*k], {i, 1, n}, {j, 1, n}, {k, 1, n}], {n, 1, 40}] (* Vaclav Kotesovec, May 10 2024 *)
PROG
(PARI) a(n) = sum(i=1, n, sum(j=1, n, sum(k=1, n, eulerphi(i*j*k)/eulerphi(j*k))));
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, May 09 2024
STATUS
approved